Converting a boolean masked value to an arithmetically masked value for cryptographic operations

ABSTRACT

A first input share value, a second input share value, and a third input share value may be received. The first input share value may be converted to a summation or subtraction between an input value and a combination of the second input share value and the third input share value. A random number value may be generated and combined with the second input share value and the third input share value to generate a combined value. Furthermore, a first output share value may be generated based on a combination of the converted first input share value, the combined value, and additional random number values.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be understood more fully from the detaileddescription given below and from the accompanying drawings of variousimplementations of the disclosure.

FIG. 1 illustrates an example device using a masked value conversioncomponent for cryptographic operations in accordance with someembodiments.

FIG. 2 is a block diagram of a masked value conversion component toprovide a conversion from a Boolean masked value to an arithmeticallymasked value for cryptographic operations in accordance with someembodiments.

FIG. 3A is a flow diagram of an example method to perform a conversionof a Boolean masked value to an arithmetically masked value forcryptographic operations in accordance with some embodiments of thepresent disclosure.

FIG. 3B illustrates a series of operations to perform the conversion ofthe Boolean masked value to the arithmetically masked value forcryptographic operations in accordance with some embodiments of thepresent disclosure.

FIG. 3C illustrates another series of operations to perform theconversion of the Boolean masked value to the arithmetically maskedvalue for cryptographic operations in accordance with some embodimentsof the present disclosure.

FIG. 3D illustrates another series of operations to perform a thirdorder conversion of the Boolean masked value to the arithmeticallymasked value in accordance with some embodiments of the presentdisclosure.

FIG. 4 is an example implementation of a hardware architecture toconvert a Boolean masked value to an arithmetically masked value inaccordance with some embodiments.

FIG. 5A is an example implementation of another hardware architecture toconvert a Boolean masked value to an arithmetically masked value inaccordance with some embodiments of the present disclosure.

FIG. 5B is an example implementation of another hardware architecture toconvert a Boolean masked value to an arithmetically masked value inaccordance with some embodiments.

FIG. 6 illustrates a block diagram of an embodiment of a computer systemin which some embodiments of the disclosure may operate.

DETAILED DESCRIPTION

Aspects of the present disclosure are directed to converting a Booleanmasked value to an arithmetically masked value for cryptographicoperations. An integrated circuit may perform a cryptographic operationthat may result in susceptibility of the integrated circuit to aside-channel attack where an attacker (e.g., an unauthorized entity) mayobtain information as the cryptographic operation is performed. Anexample of a side-channel attack includes, but is not limited to,Differential Power Analysis (DPA) where the attacker who seeks to obtaina secret key used in the cryptographic operation may study thedifferences in power consumption of the integrated circuit as thecryptographic operation is performed. An attacker may be an unauthorizedentity that may obtain the input (e.g., the secret key) to thecryptographic operation by analyzing power consumption measurements ofthe integrated circuit over a period of time. Accordingly, when thesender transmits a ciphertext to a receiver by encrypting plaintext viaa cryptographic operation, the attacker may be able to retrieve thesecret key that is used to encrypt the plaintext to the ciphertext byobserving the power consumption of the integrated circuit as thecryptographic operation is performed to encrypt the plaintext into theciphertext. For example, the attacker may uncover a cryptographic (e.g.,secret or private) key that is used to encrypt the plaintext as thecryptographic operation is performed by the integrated circuit.

Masking may be used to obfuscate or hide the input to the cryptographicoperation with random data and then the cryptographic operation may beperformed with the masked input. Such masking may render theintermediate states or values of the cryptographic operationindistinguishable from random data when an attacker of the integratedcircuit observes power consumption of the integrated circuit whenperforming the cryptographic operation. For example, the plaintext maybe subject to a Boolean operation such as an exclusive-or (XOR)operation with a random value before the cryptographic operation encodesthe plaintext into the ciphertext. Alternatively, the plaintext may besubject to an arithmetic operation such as an addition operation with arandom value before the cryptographic operation encodes the plaintextinto ciphertext. As an example, for an input x, a Boolean masked valuecorresponding to the input x may be x′ that represents (x⊕r) where r isa random number. Furthermore, for the input x, an arithmetically maskedvalue x′ may represent (x+r) where r is the random number.

Certain cryptographic operations may use both a Boolean operation and anarithmetic operation during the performance of the cryptographicoperation. For example, a cryptographic operation may perform both anXOR operation and an arithmetic (e.g., summation or subtraction)operation with masked values. The cryptographic operation may perform afirst operation based on Boolean masked values and may subsequentlyperform a second operation based on arithmetically masked values. Thus,in order to perform the arithmetic operation, the Boolean masked valuesmay need to be converted to arithmetically masked values. The conversionbetween the Boolean masked values to arithmetically masked values mayneed to be secure so that the conversion does not result in some DPAleakage (e.g., the attacker identifying information from observabledifferences in power consumption of the integrated circuit). The DPAleakage may result in an attacker may being able to obtain the secretkey (or secret-key dependent data) used in the cryptographic operationwhile performing the conversion between the Boolean masked value to thearithmetically masked value.

Accordingly, a process to efficiently and securely convert a Booleanmasked value to an arithmetically masked value may be used to perform acryptographic operation. Such a process may initiate a conversionbetween the Boolean masked value to the arithmetically masked value whenan arithmetic operation is to be performed during the cryptographicoperation. The conversion may be performed and may be implemented in anintegrated circuit to prevent DPA leaks that allow an attacker toretrieve an input to the cryptographic operation (e.g., the unmaskedvalue). Furthermore, the conversion may be performed with a fewer numberof operations. Thus, aspects of the present disclosure provideadditional security to an integrated circuit performing a cryptographicoperation as well as an increased efficiency in the performance (e.g.,less computation time) of the cryptographic operation when a Booleanmasked value is to be converted to an arithmetically masked value.

FIG. 1 illustrates an example device including a masked value conversioncomponent. In general, the device 100 may include an integrated circuitthat is associated with a masked value conversion component 111, amemory 112, and cryptographic components 113. The masked valueconversion component 111 of the integrated circuit may receive a Booleanmasked input value and may convert the Boolean masked input value to anarithmetically masked input value for use in a cryptographic operationperformed by the cryptographic components 113.

As shown in FIG. 1, the device 100 may include a masked value conversioncomponent 111 that may convert a masked input value of a first type to asecond type of masked input value. For example, the masked valuecomponent 111 may receive a Boolean masked input value or share from thememory 112 and may perform a series of operations to convert the Booleanmasked input value to an arithmetically masked input value. The maskedvalue component 111 may further receive randomly generated numbers froma random number generation component. For example, in some embodiments,the memory 112 may be used to store the randomly numbers that aregenerated by the random number generation component and the storedrandom numbers may be retrieved by the masked value conversion component111. In the same or alternative embodiments, the masked value conversioncomponent 111 may receive the random numbers from the random numbergeneration component without the random numbers being stored at thememory 112. The device components 113 may subsequently use thearithmetically masked input value in a cryptographic operation. Examplesof such cryptographic operations include, but are not limited to,generating a digital signature to authenticate the device 100 or acomponent of the device 100, encrypting or decrypting data, etc.Accordingly, the masked value conversion component 111 may convert aBoolean masked input value to an arithmetically masked input value foruse by the cryptographic components 113. Furthermore, the cryptographiccomponents 113 may perform a cryptographic operation based on thearithmetically masked input value. Examples of such cryptographicoperations may be based on, but are not limited to, Secure HashAlgorithm (SHA)-1, SHA-2, International Data Encryption Algorithm(IDEA), Rivest Cipher 6 (RC6), Extended Tiny Encryption Algorithm(XTEA), ChaCha20, Salsa20, etc.

In operation, the cryptographic components 113 may perform acryptographic operation. At a first part of the cryptographic operation,the operations that are performed by the cryptographic components 113may correspond to Boolean operations. For example, an exclusive-or (XOR)operation may be performed with a Boolean masked input value that isreceived from the memory 112 or from another component of the device100. At a second part of the cryptographic operation, the operationsthat are performed by the cryptographic components 113 may correspond toarithmetic operations. For example, an addition operation with integersmay be performed. Thus, the cryptographic operation may switch frombeing based on, or using, Boolean operations to being based on, orusing, arithmetic operations. However, since the first part of thecryptographic operation is based on the Boolean operations producesBoolean-masked values, the Boolean masked input value may first beconverted to arithmetically masked values so that the arithmeticoperations may then be performed. When the cryptographic components 113perform the arithmetic operations, then the cryptographic components 113may provide a request to the masked value conversion component 111 toconvert a Boolean masked input value stored at the memory 112. TheBoolean masked input value may be converted to an arithmetically maskedinput value and then used by the cryptographic components 113 to performarithmetic operations as part of the cryptographic operation that isbeing performed. Further details with regard to converting a Booleanmasked input value to an arithmetically masked input value are describedin conjunction with FIG. 3A.

FIG. 2 is a block diagram of a masked value conversion component 200 toconvert a Boolean masked input value to an arithmetically masked inputvalue. The masked value conversion component 200 may correspond to themasked value conversion component 111 of FIG. 1. Furthermore, the maskedvalue conversion component 200 may be implemented by or in processinglogic that may include hardware (e.g., processing device, circuitry,dedicated logic, programmable logic, microcode, integrated circuit,hardware of a device, etc.), software (e.g., instructions run orexecuted on a processing device), or a combination thereof. In someembodiments, the masked value conversion component 200 may include ashares receiver sub-component 210, a conversion indicator sub-component220, a random number generator sub-component 230, a convertersub-component 240, a combination sub-component 250, and an output maskedvalue sub-component 260. In alternative embodiments, the functionalityof one or more of the sub-components may be combined or divided.

As shown in FIG. 2, the masked value conversion component 200 mayinclude a shares receiver sub-component 210 that may receive sharescorresponding to a masked input value. The masked value conversioncomponent 200 may receive three or more shares that correspond to themasked input value. For example, a value ‘x’ may be masked by combiningthe value ‘x’ with a first random number and a second random number. Thecombination of the value ‘x’ with the first and second random numbersmay be the first share. The first random number may be the second shareand the second random number may be the third share. In someembodiments, a combination of the first share, second share, and thethird share may result in the value of ‘x.’

The masked value conversion component 200 may further include aconversion indicator sub-component 220 that may receive an indicationthat a cryptographic component that has been performing a cryptographicoperation based on a Boolean operation is now performing thecryptographic operation based on an arithmetic operation. In response toreceiving the indication, the shares receiver sub-component 210 mayreceive the first, second, and third shares from another component or amemory of a device that includes the masked value conversion component200. The random number generator sub-component 230 may generate randomnumbers for use in the conversion of the Boolean masked input value toan arithmetically masked input value.

Furthermore, the converter sub-component 240 may perform an operationwith a value represented by a combination of three values that aresubjected to an exclusive-or (XOR) operation as described in furtherdetail with regards to FIG. 3A. For example, the converter sub-component240 may convert one of the three received shares. The combinationsub-component 250 may combine multiple values to generate thearithmetically masked output value. For example, the combinationsub-component may perform an addition operation, an XOR operation,and/or a subtraction operation with multiple values. Additionally, theoutput masked value sub-component 260 may provide the result of thecombination sub-component as the converted masked value to acryptographic component performing a cryptographic operation.

FIG. 3A is a flow diagram of an example method 300 to perform aconversion of a Boolean masked value to an arithmetically masked valuefor cryptographic operations. The method 300 may be performed byprocessing logic that may include hardware (e.g., processing device,circuitry, dedicated logic, programmable logic, microcode, hardware of adevice, integrated circuit, etc.), software (e.g., instructions run orexecuted on a processing device), or a combination thereof. In someembodiments, the method 300 may be performed by the masked valueconversion component 111 of FIG. 1 or the masked value conversioncomponent 200 of FIG. 2.

As shown in FIG. 3A, the method 300 may begin, at block 310, withprocessing logic receiving a first share (x′), a second share (r₁), anda third share (r₂) where the first share represents a combination of aninput value, the second share, and the third share (x⊕r₁⊕r₂). Thus, thefirst share may represent an input value (e.g., x) that is masked bycombining the input value with the second share and the third sharebased on XOR operations. The first share may correspond to a Booleanvalue as the first share is based on the XOR operations. In someembodiments, the second share and the third share may correspond torandom numbers. For example, each of the second share and the thirdshare may correspond to different random numbers. As such, multipleshares (i.e., input shares) corresponding to a Boolean input value maybe received.

The processing logic may further convert the first share to a summationbetween the input value and an intermediate value that is representativeof the second share exclusive-or (XOR) with the third share (x+(r₁⊕r₂))(block 320). Thus, the received first share (x⊕r₁⊕r₂) may be convertedto (x+(r₁⊕r₂)). In some embodiments, an extra random value may be usedwhere the first share is changed to (x⊕r₁⊕r₂⊕α) and converted to(x+(r₁⊕r₂⊕α)) where α may correspond to a new random number. In someembodiments, another extra random value μ may be used where the firstshare is first changed to (x⊕r₁⊕r₂⊕α) and converted to (x+(r₁⊕r₂ ⊕+α))followed by an XOR operation between the intermediate value and theextra random value ((x+(r₁⊕r₂ ⊕+α)) ⊕μ) and converted to (x+(r₁⊕r₂⊕+α))+μ. The processing logic may further generate a random number (v)(block 330). In some embodiments, the random number may be differentthan the random number of the second share and the third share.Furthermore, the processing logic may combine the random number with theintermediate value (v⊕r₁⊕r₂) (block 340). For example, an XOR operationmay be performed between the generated random value and the second shareand the third share. In some embodiments, the random number may first becombined with one of the second share or the third share and the resultmay subsequently be combined with the other of the second share or thethird share so that the random number is not stored separately in amemory element or register. For example, the combined value may bestored in a register where random number and the second share arecombined to generate an intermediate value and the intermediate value isthen combined with the third share to generate the combined value. In analternative embodiment, the random number may be combined with theintermediate value that corresponds to (v+(r₁⊕r₂ ⊕+α)) as describedabove. For example, an XOR operation may be performed between thegenerated random value, the second share, the third share, and the newrandom number ‘α.’

Referring to FIG. 3A, the processing logic may further convert thecombined value of the random number and the intermediate value to asummation between the random number and the intermediate value(v+(r₁⊕r₂)) (block 350). For example, the combined value of the randomnumber with the second share and the third share may be converted to asummation (or subtraction) between the random number and a value thatrepresents the second share combined with the third share by an XORoperation. In the alternative embodiment, the processing logic mayconvert the combined value of the random number and the intermediatevalue to a subtraction between the random number and the intermediatevalue (v−(r₁⊕r₂)). The processing logic may further generate additionalrandom numbers (s₁, s₂) (block 360). In some embodiments, the additionalrandom numbers that are generated may be different than the randomnumbers corresponding to the second share and the third share. Inalternative embodiments, the additional random numbers that aregenerated may be the same as the random numbers corresponding to thesecond share and the third share. The additional random numbers maycorrespond to two new random mask values used with the original inputvalue (e.g., x). The processing logic may further combine the convertedfirst share (x+(r₁⊕r₂)) with the additional random numbers (s₁, s₂) andthe converted combined value (v+(r₁⊕r₂)) (block 370). For example, theconverted first share may be added with each of the additional randomnumbers and the converted combined value may be subtracted from theresult. For example, the processing logic may perform a summationoperation based on the converted first share and additional randomnumbers and a subtraction operation with the converted combined value(x+(r₁⊕r₂))+s₁+s₂+v−(v+(r₁⊕r₂)), (x+(r₁⊕r₂⊕α))+s₁+s₂+v−(v+(r₁⊕r₂⊕α)), or(x+(r₁⊕r₂⊕α))+μ+s₁+s₂+v−(v+(r₁⊕r₂ ⊕α))−μ. Subsequently, cryptographicoperations based on arithmetic operations may be performed. For example,the first share may correspond to a value that is equal to or representsx+s₁+s₂ that is a result of the combining of the converted first sharewith the additional random numbers and the converted combined value, thesecond share may correspond to the value s₁, and the third share maycorrespond to the value s₂. In the alternative embodiment, theprocessing logic may further combine the converted first share with oneof the additional random numbers (s₁, s₂) with the converted combinedvalue that is represented by (v−(r₁⊕r₂)) or (v−(r₁⊕r₂ ⊕α)).

In some embodiments, the subtraction operation with the convertedcombined value may be replaced by a value based on the second additionalrandom number that is summed with the results of an XOR operationbetween the second share and the third share (s₂+(r₁⊕r₂)). For example,an operation corresponding to the following equations may be performed:(x+(r₁⊕r₂))+s₁+(s₂−(r₁⊕r₂)), (x+(r₁⊕r₂⊕α))+s₁+(s₂−(r₁ ⊕r₂ ⊕α)), or(x+(r₁⊕r₂⊕α))+μ+s₁+(s₂−(r₁⊕r₂ ⊕+α))−μ. Thus, one or more additionalrandom numbers (e.g., v) may not be generated. Each of the operationsmay result in a value that corresponds to x+s₁+s₂ that may be used as anarithmetic first share.

As such, three or more shares may be received where a first sharecorresponds to a Boolean based share and the other shares correspond torandom numbers. Operations may be performed to convert the Boolean-basedshare to an arithmetic-based share. The operations may be performed inconstant time (e.g., does not depend on the input length of the Booleanmasked input value) and in fewer computation steps or operations. Forexample, the following table illustrates that the present disclosureoperates in fewer low-level instructions (Add, Subtract, XOR, etc.) thantypical Boolean to arithmetic conversion processes. The following tableshows the number of low-level instructions required by the currentstate-of-the-art compared to that required by this disclosure based ondifferent security orders (e.g., the number of masked shares that areused):

2^(nd) 3^(rd) 4^(th) 5^(th) 6^(th) 7^(th) 8^(th) Order Order Order OrderOrder Order Order  8 bits 909 1,369 1,962 2,619 3,372 4,189 5,171 16bits 1,781 2,681 3,842 5,131 6,612 8,221 10,155 32 bits 3,525 5,3057,602 10,155 13,092 16,285 20,123 64 bits 7,013 10,553 15,122 20,20326,052 32,413 40,059 Present Disclosure 31 56 115 197 331 513 763

In some embodiments, the method 300 may be performed by the series ofoperations as illustrated with respect to FIG. 3B. For example, theseries of operations may include 31 computational operations or steps toperform the method 300. In alternative embodiments of the Boolean toarithmetic conversion, the series of operations as illustrated withrespect to FIG. 3C may be performed. The series of operations of FIG. 3Cmay correspond to an implementation based on an XOR sum performed at theend of the conversion process. The Boolean to arithmetic conversionprocess may also be based on more than three input share values. Forexample, four or more input share values may be used in the conversionprocess. The series of operations of FIG. 3D may correspond to animplementation using four input share values (e.g., a third-orderBoolean-to-arithmetic mask conversion).

FIG. 4 is an hardware architecture 400 to convert a Boolean masked valueto an arithmetically masked value. The architecture 400 may correspondto the masked value conversion component 111 of FIG. 1 or the maskedvalue conversion component 200 of FIG. 2.

As shown in FIG. 4, the architecture 400 may include a first group ofmemory elements 410 (e.g., registers), a second group of memory elements420, and a third group of memory elements 430. The first group of memoryelements 410 may receive the first share, the second share, and thethird share as previously described. For example, a first register ofthe first group of memory elements 410 may store x′ which may representa Boolean value of (x⊕r₁⊕r₂) where x is the unmasked input value, r₁ isa random number and the second share, and r₂ is another random numberand the third share. Furthermore, as shown, the second register of thefirst group of memory elements 410 stores the second share r₁ and thethird register of the first group of memory elements 410 stores thethird share r₂. The second group of memory elements 420 may receive andstore various random numbers that are generated for use in theconverting of the Boolean shares to the arithmetic shares. For example,the registers of the second group of memory elements 420 may storerandom numbers to convert the first share and additional randomlygenerated numbers as previously described.

The architecture 400 may include a series of exclusive-or (XOR) gates,adders, and subtractor components as illustrated in FIG. 4. The outputsof the architecture 400 may be stored at the third group of memoryelements 430. For example, a combination of the values stored atregisters of the first group 410 and the second group 420 may be used togenerate the arithmetic share that is converted from the Boolean share.Thus, a first register of the third group of memory elements 430 maystore the converted first share (e.g., x′), and a second and thirdregister of the third group of memory elements 430 may store additionalmask values (e.g., s₁ and s₂).

Thus, the first group of memory elements 410 may store the sharescorresponding to the Boolean masked input, the second group of memoryelements 420 may store randomly generated numbers that are used in theconversion process, and the third group of memory elements 430 may storethe shares corresponding to the arithmetically masked value.

FIG. 5A is an example implementation of a hardware architecture 500 toconvert a Boolean masked value to an arithmetically masked value. Thearchitecture 500 may correspond to the masked value conversion component111 of FIG. 1 or the masked value conversion component 200 of FIG. 2.

As shown in FIG. 5A, the architecture 500 may include a first group ofmemory elements 510 and a second group of memory elements 520. The firstgroup of memory elements 510 may store the first share, the secondshare, and the third share corresponding to a Boolean masked input valueas previously described. Various functions corresponding to thefunctionality of the logic of architecture 400 may split or divide theprocess of converting the Boolean masked input value to anarithmetically masked input value. For example, each of the functionsF₁, F₂, and F₃ may perform a portion of the conversion process orinclude a portion of the logic of the architecture 400. Furthermore,each of the functions F₁, F₂, and F₃ may receive a subset of the shares.For example, each of the functions may receive two of the three sharescorresponding to the Boolean masked input value. Subsequently, theoutputs of the functions may be combined and stored at the second groupof memory elements 520 to store the first share, second share, and thirdshare for the arithmetically masked input value that has been convertedfrom the Boolean masked input value. In alternative embodiments, theoutputs of the functions may not be combined.

FIG. 5B is another hardware architecture 550 to convert a Boolean maskedvalue to an arithmetically masked value. The architecture 550 maycorrespond to the masked value conversion component 111 of FIG. 1 or themasked value conversion component 200 of FIG. 2.

As shown in FIG. 5B, the architecture 500 may include a first group ofmemory elements 560, a second group of memory elements 570, and a thirdgroup of memory elements 580. The registers of the first group of memoryelements 560 may receive and store the first share, the second share,and the third share corresponding to a Boolean masked input value thatis to be converted to the arithmetically masked input value. A first setof functions F₁₁, F₁₂, F₁₃, and F₁₄ may perform a first portion of theconversion process and the results of the first portion of theconversion process may be stored at the registers of the second group ofmemory elements 570. In some embodiments, the number of shares may beincreased or expanded by using additional functions as shown in FIG. 5B.For example, the Boolean masked input value of three shares may beincreased to four intermediate shares and stored at the second group ofmemory elements 570. Subsequently, a second set of functions F₂₁, F₂₂,and F₂₃ may perform a second portion of the conversion process and theresults of the second portion of the conversion process may be stored atthe registers of the third group of the memory elements 580. The secondset of functions may receive the four intermediate shares and generate afewer number of shares that correspond to the arithmetically maskedinput value. For example, four intermediate shares may be used by thethree functions of the second set of functions to generate the threeshares corresponding to the arithmetically masked input value. AlthoughFIG. 5B illustrates two sets of functions, the architecture to convertthe Boolean masked value to the arithmetically masked value may includeany number of sets of functions.

FIG. 6 illustrates an example machine of a computer system 600 withinwhich a set of instructions, for causing the machine to perform any oneor more of the methodologies discussed herein, may be executed. Inalternative implementations, the machine may be connected (e.g.,networked) to other machines in a LAN, an intranet, an extranet, and/orthe Internet. The machine may operate in the capacity of a server or aclient machine in client-server network environment, as a peer machinein a peer-to-peer (or distributed) network environment, or as a serveror a client machine in a cloud computing infrastructure or environment.

The machine may be a personal computer (PC), a tablet PC, a set-top box(STB), a Personal Digital Assistant (PDA), a cellular telephone, a webappliance, a server, a network router, a switch or bridge, or anymachine capable of executing a set of instructions (sequential orotherwise) that specify actions to be taken by that machine. Further,while a single machine is illustrated, the term “machine” shall also betaken to include any collection of machines that individually or jointlyexecute a set (or multiple sets) of instructions to perform any one ormore of the methodologies discussed herein.

The example computer system 600 includes a processing device 602, a mainmemory 604 (e.g., read-only memory (ROM), flash memory, dynamic randomaccess memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM(RDRAM), etc.), a static memory 606 (e.g., flash memory, static randomaccess memory (SRAM), etc.), and a data storage device 618, whichcommunicate with each other via a bus 630.

Processing device 602 represents one or more general-purpose processingdevices such as a microprocessor, a central processing unit, or thelike. More particularly, the processing device may be complexinstruction set computing (CISC) microprocessor, reduced instruction setcomputing (RISC) microprocessor, very long instruction word (VLIW)microprocessor, or processor implementing other instruction sets, orprocessors implementing a combination of instruction sets. Processingdevice 602 may also be one or more special-purpose processing devicessuch as an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA), a digital signal processor (DSP),network processor, or the like. The processing device 602 is configuredto execute instructions 626 for performing the operations and stepsdiscussed herein.

The computer system 600 may further include a network interface device608 to communicate over the network 620. The computer system 600 alsomay include a video display unit 610 (e.g., a liquid crystal display(LCD) or a cathode ray tube (CRT)), an alphanumeric input device 612(e.g., a keyboard), a cursor control device 614 (e.g., a mouse), agraphics processing unit 622, a signal generation device 616 (e.g., aspeaker), graphics processing unit 622, video processing unit 628, andaudio processing unit 632.

The data storage device 618 may include a machine-readable storagemedium 624 (also known as a computer-readable medium) on which is storedone or more sets of instructions or software 626 embodying any one ormore of the methodologies or functions described herein. Theinstructions 626 may also reside, completely or at least partially,within the main memory 604 and/or within the processing device 602during execution thereof by the computer system 600, the main memory 604and the processing device 602 also constituting machine-readable storagemedia.

In one implementation, the instructions 626 include instructions toimplement functionality corresponding to a masked value conversioncomponent (e.g., masked value conversion component 111 of FIG. 1 ormasked value conversion component 200 of FIG. 2). While themachine-readable storage medium 624 is shown in an exampleimplementation to be a single medium, the term “machine-readable storagemedium” should be taken to include a single medium or multiple media(e.g., a centralized or distributed database, and/or associated cachesand servers) that store the one or more sets of instructions. The term“machine-readable storage medium” shall also be taken to include anymedium that is capable of storing or encoding a set of instructions forexecution by the machine and that cause the machine to perform any oneor more of the methodologies of the present disclosure. The term“machine-readable storage medium” shall accordingly be taken to include,but not be limited to, solid-state memories, optical media and magneticmedia.

Some portions of the preceding detailed descriptions have been presentedin terms of algorithms and symbolic representations of operations ondata bits within a computer memory. These algorithmic descriptions andrepresentations are the ways used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of operations leading to adesired result. The operations are those requiring physicalmanipulations of physical quantities. Usually, though not necessarily,these quantities take the form of electrical or magnetic signals capableof being stored, combined, compared, and otherwise manipulated. It hasproven convenient at times, principally for reasons of common usage, torefer to these signals as bits, values, elements, symbols, characters,terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantities. Unlessspecifically stated otherwise as apparent from the above discussion, itis appreciated that throughout the description, discussions utilizingterms such as “identifying” or “determining” or “executing” or“performing” or “collecting” or “creating” or “sending” or the like,refer to the action and processes of a computer system, or similarelectronic computing device, that manipulates and transforms datarepresented as physical (electronic) quantities within the computersystem's registers and memories into other data similarly represented asphysical quantities within the computer system memories or registers orother such information storage devices.

The present disclosure also relates to an apparatus for performing theoperations herein. This apparatus may be specially constructed for theintended purposes, or it may comprise a general purpose computerselectively activated or reconfigured by a computer program stored inthe computer. Such a computer program may be stored in a computerreadable storage medium, such as, but not limited to, any type of diskincluding floppy disks, optical disks, CD-ROMs, and magnetic-opticaldisks, read-only memories (ROMs), random access memories (RAMs), EPROMs,EEPROMs, magnetic or optical cards, or any type of media suitable forstoring electronic instructions, each coupled to a computer system bus.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general purposesystems may be used with programs in accordance with the teachingsherein, or it may prove convenient to construct a more specializedapparatus to perform the method. The structure for a variety of thesesystems will appear as set forth in the description below. In addition,the present disclosure is not described with reference to any particularprogramming language. It will be appreciated that a variety ofprogramming languages may be used to implement the teachings of thedisclosure as described herein.

The present disclosure may be provided as a computer program product, orsoftware, that may include a machine-readable medium having storedthereon instructions, which may be used to program a computer system (orother electronic devices) to perform a process according to the presentdisclosure. A machine-readable medium includes any mechanism for storinginformation in a form readable by a machine (e.g., a computer). Forexample, a machine-readable (e.g., computer-readable) medium includes amachine (e.g., a computer) readable storage medium such as a read onlymemory (“ROM”), random access memory (“RAM”), magnetic disk storagemedia, optical storage media, flash memory devices, etc.

In the foregoing specification, implementations of the disclosure havebeen described with reference to specific example implementationsthereof. It will be evident that various modifications may be madethereto without departing from the broader spirit and scope ofimplementations of the disclosure as set forth in the following claims.The specification and drawings are, accordingly, to be regarded in anillustrative sense rather than a restrictive sense.

What is claimed is:
 1. A system comprising: a first set of registers tostore a first input share value, a second input share value, and a thirdinput share value, the first input share value representing a Booleancombination between an input value, the second input share value, andthe third input share value; a second set of registers to store a firstoutput share value, a second output share value, and a third outputshare value, the first output share value representing an arithmeticcombination between the input value, the second output share value, andthe third output share value; a cryptographic component to perform acryptographic operation based on a Boolean operation and an arithmeticoperation; and a processing device, operatively coupled with the firstset of registers and the second set of registers, to: receive anindication that the cryptographic operation being performed by thecryptographic component has switched from using the Boolean operation tousing the arithmetic operation; in response to the indication, receivethe first, second, and third input share values from the first set ofregisters; convert the first input share value to a summation or asubtraction between the input value and a combination of the secondinput share value and the third input share value; generate a randomnumber value; combine the random number value with the second inputshare value and the third input share value to generate a combinedvalue; generate additional random number values; and generate the firstoutput share value based on a combination of the converted first inputshare value, the combined value, and the additional random numbervalues.
 2. The system of claim 1, wherein a first random number of theadditional random number values corresponds to the second output sharevalue and a second random number of the additional random number valuescorresponds to the third output share value, and wherein the firstoutput share value represents a summation or a subtraction between theinput value, the first random number, and the second random number. 3.The system of claim 1, wherein the processing device is further to:receive at least one additional input share value, the generating of thefirst output share value being further based on the at least oneadditional input share value.
 4. The system of claim 1, wherein tocombine the random number value with the second input share value andthe third input share value to generate the combined value, theprocessing device is further to: at a first time, perform an XORoperation between the random number value and the second input sharevalue to generate an intermediate value; at a second time after thefirst time, perform the XOR operation between the intermediate value andthe third input share value to generate a second intermediate value; andconvert the second intermediate value to the combined value.
 5. Thesystem of claim 1, wherein the second output share value and the thirdoutput share value are the same as the second input share value and thethird input share value.
 6. The system of claim 1, wherein the secondoutput share value and the third output share value are each differentthan the second input share value and the third input share value. 7.The system of claim 1, wherein to generate the first output share value,the processing device is further to: perform a summation or asubtraction between the converted first input share value and theadditional random number values; and perform a subtraction operationbetween a result of the summation or the subtraction and the combinedvalue.
 8. A method comprising: performing a cryptographic operation witha Boolean operation; receiving an indication that the cryptographicoperation has switched from using the Boolean operation to an arithmeticoperation; in response to receiving the indication, receiving a firstinput share value, a second input share value, and a third input sharevalue; converting the first input share value to a summation or asubtraction between an input value and a combination of the second inputshare value and the third input share value; generating a random numbervalue; combining the random number value with the second input sharevalue and the third input share value to generate a combined value;generating, by a processing device, a first output share value based ona combination of the converted first input share value, the combinedvalue, and additional random number values; and performing thecryptographic operation with the arithmetic operation by using the firstoutput share.
 9. The method of claim 8, wherein combining the randomnumber value with the second input share value and the third input sharevalue to generate the combined value comprises: at a first time,performing an XOR operation between the random number value and thesecond input share value to generate an intermediate value; at a secondtime after the first time, performing the XOR operation between theintermediate value, the third input share value, and another randomnumber value to generate a second intermediate value; and convert thesecond intermediate value to the combined value
 10. The method of claim8, further comprising: receiving at least one additional input sharevalue, the generating of the output share value being further based onthe at least one additional input share value.
 11. The method of claim8, wherein combining the random number value with the second input sharevalue and the third input share value to generate the combined valuecomprises: at a first time, perform an XOR operation between the randomnumber value and the second input share value to generate anintermediate value; at a second time after the first time, perform theXOR operation between the intermediate value and the third input sharevalue to generate a second intermediate value; and convert the secondintermediate value to the combined value.
 12. The method of claim 8,wherein a second output share value and a third output share valueassociated with the first output share value are the same as the secondinput share value and the third input share value.
 13. The method ofclaim 8, wherein a second output share value and a third output sharevalue associated with the first output share value are each differentthan the second input share value and the third input share value. 14.The method of claim 8, wherein generating the first output share valuecomprises: performing a summation or a subtraction between the convertedfirst input share value and the additional random number values; andperforming a subtraction operation between a result of the summation orthe subtraction and the combined value.
 15. A non-transitory computerreadable medium including data that, when accessed by a processingdevice, cause the processing device to perform operations comprising:performing a cryptographic operation with a Boolean operation; receivingan indication that the cryptographic operation has switched from usingthe Boolean operation to an arithmetic operation; in response toreceiving the indication, receiving a first input share value, a secondinput share value, and a third input share value; converting the firstinput share value to a summation or a subtraction between an input valueand a combination of the second input share value and the third inputshare value; generating a random number value; combining the randomnumber value with the second input share value and the third input sharevalue to generate a combined value; generating a first output sharevalue based on a combination of the converted first share value, thecombined value, and additional random number values; and performing thecryptographic operation with the arithmetic operation by using the firstoutput share.
 16. The non-transitory computer readable medium of claim15, wherein to combine the random number value with the second inputshare value and the third input share value to generate the combinedvalue, the operations further comprise: at a first time, perform an XORoperation between the random number value and the second input sharevalue to generate an intermediate value; at a second time after thefirst time, perform the XOR operation between the intermediate value,the third input share value, and another random number value to generatea second intermediate value; and convert the second intermediate valueto the combined value.
 17. The non-transitory computer readable mediumof claim 15, the operations further comprising: receiving at least oneadditional input share value, the generating of the output share valuebeing further based on the at least one additional input share value.18. The non-transitory computer readable medium of claim 15, wherein tocombine the random number value with the second input share value andthe third input share value to generate the combined value, theoperations further comprise: at a first time, perform an XOR operationbetween the random number value and the second input share value togenerate an intermediate value; at a second time after the first time,perform the XOR operation between the intermediate value and the thirdinput share value to generate a second intermediate value; and convertthe second intermediate value to the combined value.
 19. Thenon-transitory computer readable medium of claim 15, wherein to generatethe first output share value, the operations further comprise:performing a summation or a subtraction between the converted firstinput share value and the additional random number values; andperforming a subtraction operation between a result of the summation orthe subtraction and the combined value.
 20. The non-transitory computerreadable medium of claim 15, wherein a second output share value and athird output share value associated with the first output share valueare the same as the second input share value and the third input sharevalue.
 21. The system of claim 1, wherein the processing device isfurther to: receive another random number value, wherein the convertingof the first input share value is further based on an addition orsubtraction of the another random number value.
 22. The method of claim8, further comprising: receiving another random number value, whereinthe converting of the first input share value is further based on anaddition or subtraction of the another random number value.
 23. Thenon-transitory computer readable medium of claim 15, wherein theoperations further comprise: receiving another random number value,wherein the converting of the first input share value is further basedon an addition or subtraction of the another random number value.